Closes gh-18098

* pr/18092:
  Remove duplicated dependency in spring-boot-docs

Closes gh-18092

See gh-18092

* pr/18089:
  Remove unnecessary blank lines

Closes gh-18089

See gh-18089

Closes gh-18094

Fixes gh-17974

Closes gh-18093

Fixes gh-17550

Reverts commit 2be3027d
on 2.1.x

See gh-17539

Closes gh-18085

* pr/17539:
  Polish "Ensure Flyway/Liquibase runs before Quartz"
  Ensure Flyway/Liquibase runs before Quartz

Closes gh-17539

See gh-17539

Add post processors to ensure that SchedulerFactoryBean and Scheduler
beans depend on the Flyway and Liquibase beans.

See gh-17539

Closes gh-18084

Fixes gh-17579

Closes gh-18083

Fixes gh-17541

* pr/18004:
  Fix duplicated words

Closes gh-18004

See gh-18004

* pr/18077:
  Simplify some code

Closes gh-18077

See gh-18077

Closes gh-18081

Closes gh-17814

Closes gh-18080

Closes gh-17933

Closes gh-18079

Update the reference guide with a note about using environment variables
to configure logging.

Closes gh-17958

This reverts commit f6f99d78 as 9.4.20
includes an incompatible class change where an abstract class in
Jetty's public API was changed to an interface, making it incompatible
with Framework 5.1.9.

See gh-18035

Closes gh-18075

Closes gh-18074